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Underground microbes eat into oil reserves

Media release

C248/08

8 September 2008

Research paper published online in prestigious Nature Geoscience Journal

The discovery of live anaerobic bacteria in petroleum reservoirs deep below the Earth’s surface will offer industry answers, as it struggles to identify the reasons for large variations in oil quality.

Scientists from Curtin University of Technology and the University of Cologne in Germany were the first to discover the phospholipid fatty acids (PLFAs) indicators for live bacteria in deep petroleum reservoirs.  They believe that their findings provide additional explanations about underground microbes and their role in degrading oil reservoirs.

Professor Kliti Grice is the Research Director of the WA Organic and Isotope Geochemistry Centre (WA-OIGC) at Curtin and has over 15 years experience identifying organisms and biomarkers in sedimentary organic matter and petroleum.  She worked closely with lead authors, Christian Hallmann and Professor Lorenz Schwark, based at the University of Cologne, to write their recently published paper “Community dynamics of anaerobic bacteria in deep petroleum reservoirs”.

“ We have shown the presence of live bacteria in these deep reservoirs and show they are changing the oil quality,” Professor Grice said.

The petroleum samples studied originated from sediments up to 2,000 metres deep and up to 145 million years old and were analysed by looking at bacterial fatty acids (PLFAs) that indicate the presence of phospholipids – molecular markers for live bacteria. This is the deepest occurrence of microbes in sediments reported so far.

“These deep microbes can have enormous implications for our natural environment as they influence various biogeochemical cycles and thereby potentially affect Earth’s climate,” Christian Hallmann said.

WA-OIGC have extracted and analysed specific PLFAs in biofilms from potable and recycled waters and measured their stable isotopic compositions reflecting modes of biosynthesis in bacteria (a current Curtin PhD study of Dawn White).

“Discovering PLFAs in oil especially opens many new opportunities for further studies into the deep biosphere.  We hope to increase our knowledge of biodegradation and indicate which microbes are responsible for degrading the oil,” Professor Grice said.

This research was supported by the University of Cologne, a Curtin University International Research Tuition Scholarship and PhD stipend award, a travel scholarship from the European Association of Organic Geochemists and a grant-in-aid from the American Association of Petroleum Geologists to Curtin PhD scholar Christian Hallmann.

Modified: 8 September 2008